Conservative religious leaders from across the country are pouring time, talent and millions of dollars into the state in support of Proposition 8, which would put a ban on same-sex marriage into the state Constitution. The hope is to reverse a California Supreme Court ruling in May that gave same-sex couples permission to marry.

Michigan: Proposal 2

For 20 years, state law has banned the use of embryonic stem cells in medical research, but this ballot proposal would amend the state Constitution to allow researchers to use donated embryos from fertility treatments to make embryonic stem cell lines for disease research. Proponents say the ban has stifled life sciences research in the state, but the ballot amendment has ignited opposition from antiabortion groups.

North Carolina, Senate: Sen. Elizabeth Dole (R) vs. Kay R. Hagan (D)

Before this campaign season, Dole was not considered a vulnerable incumbent. As Washington royalty with a gold-plated resume, she won the seat once held by Sen. Jesse Helms by a nine-point margin in 2002. But as economic turmoil has driven down support for Republican candidates, several polls suggest that Hagan, a relatively unknown Democratic state senator from Greensboro, has closed Dole's double-digit lead or even pulled ahead.

Minnesota, Senate: Sen. Norm Coleman (R) vs. Al Franken (D)

The Senate race between comedian and author Franken and the incumbent Coleman has been the most expensive in the country — and is now considered a tossup. Complicating the race is the Independence Party's Dean Bark­ley, a Jesse Ventura ally who is polling in the high teens. Franken stumbled early with tax issues and had to apologize for some of his offensive comedy material. But he's come back by calling Coleman a tool of special interests and has made hay with Coleman's cheap ($600 a month) rent for a Washington apartment owned by a lobbyist.

Kentucky, Senate: Sen. Mitch McConnell (R) vs. Bruce Lunsford (D)

McConnell, the Senate minority leader, is one of at least a half-dozen Republican incumbents in danger of being booted simply because it's an awful year to be a Republican. McConnell leads Lunsford, a wealthy former health care executive, by about 4 percentage points in an average of Kentucky polls compiled by RealClearPolitics. McConnell's wife, Elaine Chao, is secretary of labor, the longest-serving member in the Bush Cabinet. As he campaigns across the state, McConnell is stalked by a man in a chicken suit, saying the senator is afraid to debate Lunsford.

New Hampshire, Senate: Sen. John Sununu (R) vs. Jeanne Shaheen (D)

It is a sign of how dismal the climate is for Republicans that Sununu, a rising GOP prospect at age 44, faces daunting odds despite a reputation as a capable, if not particularly charismatic, senator with a fiscally conservative profile that is a good fit for the state. Sununu, the son of former New Hampshire Gov. John Sununu, who was chief of staff for the first President Bush, said in an interview that plenty of voters have told him they are voting for both him and Barack Obama. Still, with Sununu facing headwinds, former Gov. Shaheen is playing it safe, in keeping with her reputation for caution and discipline. She lost to Sununu in 2002 by four points.

Alaska, Senate: Sen. Ted Stevens (R) vs. Mark Begich (D)

Elected in 1970, Stevens is the Senate's longest-serving Republican. He made his name, and wielded his power, on the Appropriations Committee, where he lavished his state with federal spending. But his tenure seems likely to end at the hands of Anchorage Mayor Begich, who leads in some polls by as many as eight points. Why? Because Stevens was convicted on seven counts of making false statements on his financial disclosure forms to conceal gifts from an oil services company. Stevens has proclaimed his innocence.

Oregon, Senate: Gordon Smith (R) vs. Jeff Merkley (D)

Smith is a moderate Republican in the mold of those Northeast Republicans who have become so scarce. Last year, Smith voted with a majority of his party only 55 percent of the time. Political analysts rate this one a tossup. Smith is eager to prove his bipartisan credentials and has run ads touting his friendship with such Democrats as Barack Obama and Edward Kennedy. Merkley points out that Smith voted with President Bush 80 percent of the time. That might be low among Republicans, but it might be too high in the anti-Bush environment.

Mississippi, Senate: Sen. Roger Wicker (R) vs. Ronnie Musgrove (D)

In 2006, Wicker won 64 percent of the vote in a special election to complete the term of retiring Sen. Trent Lott. But two years later, Wicker's fate — and the GOP's long-held grip on Dixie — could be headed for a reversal. Pollsters and analysts say there is no clear favorite in the race between the former House member and the former governor. Musgrove is hoping Barack Obama's formidable ground machine drives up turnout, but he hasn't aligned himself too closely with the presidential candidate, who looks a bit too liberal to many Southern conservatives who might be about ready to abandon the GOP for the right candidate.

Colorado, Senate: Rep. Mark Udall (D) vs. Bob Schaffer (R)

This seat is vacant because of the retirement of Republican Wayne Allard, who might have had trouble keeping the seat in GOP hands even as an incumbent. As it is, Democrats consider this a prime opportunity to gain a seat in the Senate, and analysts say the race currently favors Udall. It is a sign of how much the national political climate has shifted that Udall, who hails from the liberal Boulder region of the state and has a voting record to match it, is running so strong against the more conservative Schaffer. But this is a year in which Barack Obama is favored to carry Colorado, a state that has only once (in 1992) interrupted its support for Republican presidential candidates since 1968.

New Mexico, Senate: Rep. Steve Pearce (R) vs. Rep. Tom Udall (D)

Another retiring Republican has given Democrats hope for picking up a seat. Pete V. Domenici, a fearless budget hawk who has held office since 1972, is retiring. Two sitting House members are vying for the seat, but the experts say it's tilting heavily for Udall (a cousin of Colorado's Mark Udall), who has a solidly liberal voting record and has focused his House career on energy and environmental issues. Pearce, who calls himself "very conservative," has lagged badly in the polls. The National Republican Senatorial Committee stopped spending in the race for Pearce.

Louisiana, Senate: Sen. Mary Landrieu (D) vs. John Kennedy (R)

Landrieu is the only Democrat in the Senate whose re-election is in doubt. She has held the seat since 1996 and has won both previous races by very slim margins. This time, her opponent is Republican state Treasurer John Kennedy, a former Democrat who says he embodies the "conservative change " of presidential candidate John McCain, who is expected to carry the state. The National Republican Senatorial Committee planned to abandon Kennedy, but reversed course as polls showed a tightening race.